uv filters

I have been looking for the right UV filter to put on my new 70-300 f/4-5.6L and I want to buy a 77mm so I can use it on my other lenses also and just use a step up ring on the new lens. Here is where I need your help I have been looking at the Singh ray Hi-Lux UV filters and the Heliopan UV filters. I do alot of flash photography and read where the high lux cuts down on blue cast of flash and is a step down from 81A filter. Just want to know if anyone else uses this filter and is it good for flash work only or can it be left on full time. Have also sceen the very pricy Heliopan dilgital filter and wondering if it is worth it or not? If any one else uses this filter I would like to know your opion of it. I have dropped alot of chedder on this new lens purchace and figure why skimp on the filter purchace now. Your suggestions are very app. Thanks.